 Since the p185her2/neu-ECD is human-derived, a eukaryotic expression system may 
be a better choice if we want to express it precisely. Based on this consideration, the  
p185her2/neu-ECD DNA sequence, the 8 mutants and the 9 Antigen-Mcherry fused 
proteins will be inserted into pPICZα-a plasmid (using EcoRI and XbaI) for Pichia 
Pastoris Yeast expression. 